Percussion fuse for projectiles



L. E. REMONDY I PERCUSSION FUSE FOR PROJECTILES Nov. 22, 1938.

Filed Dec. 4, i955 Patented Nov. 22, 1938 STATS l FHQ Application December 4, 1935, Serial No. 52,914 In France January 29, 1935 8 Claims.

This invention relates to extremely sensitive percussion fuses of the type embodying a striker device or firing pin of exceptional lightness intended to operate by being forced-in on impact under the effect of encountering an obstacle of even very slight resistance, such as aircraft fabric, for example, and is more particularly dirooted to the manner of securing such a striker to the fuse body.

One of the principal difficulties encountered heretofore in the construction of an extremely light striker resides in the necessity of effectively ensuring the fixity of the striker with respect to H the fuse body at all times until an obstacle is 75 encountered. For this retention of the striker to be perfectly effective, it is absolutely necessary that it should be capable of resisting the static stresses which become operative under the effect of the inertia of the striker upon the departure of 39 the shot and also under the action of the pressure of the air. On the contrary, it is necessary that under the effect of a dynamic force, even of relatively slight magnitude, the retention device should become inoperative in order to enable the striker to be driven in with a view to the operation of the fuse, which operation may be followed, if

desired, by an operation due, to the inertia of a movable percusson cap support. It is also highly important that the percussion caps of fuses of 30 this character be preserved in proper working condition even though stored for long intervals of time or exposed to adverse atmospheric conditions such as would tend to produce deterioration thereof because of the absorption of moisture or 35 the like.

It is quite difiicult in practice, however, to provide a striker securing device of these characteristics by employing the usual means such as one or more pins passing through the striker and intended to be sheared upon the impact against an obstacle. If these pins are to offer a sufficient resistance to the static stresses, they must be constructed with a relatively large diameter. which involves a weakening of the body or head of the striker at the points where these pins pass through; this in turn requires a corresponding strengthening of the said body or head, which strengthening is accompanied by an increase in weight and mass. This increase in mass and diameter can only be secured at the expense of the lightness of the striker and hence of the sensitivity of the fuse. Furthermore, such securing means do not provide sufiicient tightness of fit 55 between the elements of the fuse to insure protection of the percussion cap against deterioration due to contact with the atmosphere.

According to the present invention, the fuse body is provided at its forward end with an out wardly opening chamber in which is housed the '5 enlarged head of the striker and with which is combined means for preventing movement of the striker outwardly therefrom. The stem or rod of the striker is integral with its fixing member, and the latter is so disposed as to be supported directly 10 on the fuse body or on a member fixed in the said body, and is in addition so constituted as to offer an excellent resistance appropriate to the static stresses which are produced on the firing of the projectile and yet break readily under the 16 effect of even a very slight dynamic stress-such as the impact against an obstacle of very slight resistance. In practice, the member for fixing the striker by direct support on the fuse body com-- prises a thin, continuous, solid or perforated col- 20 lar or collar elements. If desired, the means which serve to prevent any untimely outward movement of the striker from the fuse body may be associated with the supporting collar. Such a collar of small thickness constitutes an excellent resistance to the static stresses which are produced on the firing of the projectile while, on the other hand, it has a very pronounced fragility under the effect of an impact, in other words a dynamic stress even of relatively very slight magnitude. With this construction. the collar or collar elements become detached from the rest of the striker with considerable facility under the effect of an impact, whereas they resist perfectly well a static stress even when exerted with a considerable force.

Various forms of construction of the invention are shown by way of examples in the accompanying drawing, wherein:--

, 'Figure l is an axial sectional view of the for- 40 ward end of one form of fuse mechanism embodying the present invention;

Figure 2 is a view similar to Figure 1 of another embodiment of the invention;

Figure 2a is a cross section taken substantially on line IIII of Figure 2;

Figure 3 is an axial section of still another form of the invention;

Figure 3a is a cross section taken substantially on line IIIIII of Figure 3; and

Figure 4 is an axial section of a still different embodiment of the invention.

In Figure 1, a denotes the fuse body and b the rod of an extra-light striker having a large head b housed. in a chamber a formed in the forward end of fuse body a, the rod being engaged in an axial cOndlllt 01 leading to the percussion cap of the fuse and'carrying integral with it a collar 0, the lower face of which rests on a shoulder a provided on the fuse body. In this first example, any untimely outward movement of the striker from chamber a of the fuse body is prevented in the known manner by a cap e which may at the same time form a gas-tight cap preventing the ingress into the interior of the fuse body of the atmosphere, but the resistance of which is sufficiently slight for it not to oppose the drivingin.

of the head of the striker upon encountering an obstacle.

Figures 2 and 2a. show a second form of construction in which the collar 0 integral with the rod 2) of the striker rests with its lower face on a shoulder a of the fuse body formed on a recessed, externally screwthreaded part of the latter. In this case, the retention of the striker against any untimely outward movement from chamber a of the fuse body is provided by means of a screw-threaded cap f having a radially positioned slot f adapted to receive the upper part b of the rod of the striker. The base of the cap 1 bears on the upper face of the collar 0, the latter being thus clamped between the shoulder a and the base of the said screw-threaded cap.

Figures 3 and 3a show another constructional example in which the fuse body is made in two elements a (1 adapted to be secured together by a screw threaded connection. The element a? has formed thereon a shoulder a and the collar 0 is clamped between the shoulder a of the element a and the shoulder a of the element a with the interposition of a washer g having, as shown in plan in Figure 3a, a radially extending slot 0 for the reception of the upper part b of the striker rod.

As shown in Figures 2 and 3, a gasket is having only an insignificant resistance is interposed between the collar 0 and its supporting shoulder a in order to effectively seal the conduitd leading to the percussion cap against the entrance of air and moisture.

In the example of Figure a, the collar 0 instead of resting directly on the fuse body a, is supported on a shoulder h formed'on the upper part-of a sleeve h serving as guide for the striker rod and comprising in its lower part a recess h for the percussion cap 2'. Any untimely outward movement of the striker, and at the same time of the sleeve h and the percussion cap 2', is prevented in the manner known per se by beading the uper rim a of the fuse body over on the head 12 of the striker. A ring 9' of plastic material is then interposed between the beaded over rim a and the periphery of the striker head b so as to form an air-tight and moisture-proof joint which will protect the percussion cap 2' against deterioration.

Of course, the striker device described may be associated with any of the usual well-known safety devices commonly employed in percussion fuses operating by the driving in of the striker and the inertia of the percussion cap support.

Although a number of different forms of the invention have been described and illustrated'in the accompanying drawing, it will be obvious that the invention is not limitedto the specific structures disclosed but is capable of a variety of mechanical embodiments. Various changes, which will now suggest themselves to those skilled in the art, may be made in the form, details of construction and arrangement of the parts without departing from the spirit of the invention. Reference is therefore to be had to the appended claims for a definition of the limits of the invention.

What is claimed is:-

1. In a percussion fuse for projectiles of the sensitive type adapted to operate by the driving in of the striker upon impact, a fuse body having formed in the forward end thereof an open ended chamber, a striker member having an enlarged head housed in said chamber adjacent the open end thereof and a stem extending into and guided by an axial passageway formed in said fuse body, a shoulder fixed with respect to said fuse body, a collar element formed integrally with said striker stem and resting upon said shoulder so as to normally prevent inward movement of said striker member relative to said fuse body, said collar element being so constructed as to resist without fracture the static stresses produced upon firing of the projectile due to the inertia of the striker member but to shear easily from the striker stem under the effect of even relatively slight dynamic stresses produced upon impact, a striker restraining member positioned within said chamber beneath said enlarged striker head and engaging the outer surface of said collar element, said member having a radially extending opening therein to receive said striker stem, and means for fixing said striker restraining member with respect to the fuse body so as to prevent movement of said striker member outwardly through the open end of said chamber.

2. A percussion fuse according to claim 1 including means associated with said striker restraining member and collar element for preventing the entrance of air and moisture into the axial passageway into which the striker stem exends.

3. In a percussion fuse for projectiles of the sensitive type adapted to operate by the driving in of the striker upon impact, a fuse body having formed in the forward end thereof an open ended chamber, a striker member having an enlarged head housed in said chamber adjacent the open end thereof and a .stem extending into and guided by an axial passageway formed in said fuse body, a shoulder fixed with respect to said fuse body, a collar element formed integrally with said striker stem and resting upon said shoulder so as to normally prevent inward movement of said striker member relative to said fuse body, said collar element being so constructed as to resist without fracture the static stresses produced upon firing of the projectile due to the inertia of the striker member but to shear easily from the striker stem under the effect of even relatively slight dynamic stresses produced upon impact, and means for preventing movement of said striker member outwardly through the open end of said chamber, said means comprising a cap member positioned within said chamber beneath said enlarged striker head and having a screw-threaded connection with a portion of said fuse body, said cap member having a radially extending opening in the side and end walls thereof to receive said striker stem and bearing upon the outer surface of said. collar element so as to hold the inner surface of said element against said shoulder.

l. A percussion fuse according to claim '3 including a gasket tightly clamped between the collar element and the shoulder upon which said element is supported.

5. In a percussion fuse for projectiles of the sensitive type adapted to operate by the driving in of the striker upon impact, a fuse body including two separable elements normally connected together and having formed in the forward end thereof an open ended chamber, astriker member having an enlarged head housed in said chamber adjacent the open end thereof and a stem extending into and guided by an axial passageway formed in said fuse body, a shoulder fixed with respect to one of said elements of said fuse body, a collar element formed integrally with said striker stem and resting upon said shoulder so as to normally prevent inward movement of said striker member relative to said fuse body, said collar element being so constructed as to resist without fracture the static stresses produced upon firing of the projectile due to the inertia of the striker member but to shear easily from the striker stem under the effect of even relatively slight dynamic stresses produced upon impact, and means for preventing movement of said striker member outwardly through the open end of said chamber, said means comprising a washer bearing on the outer surface of said collar element and having a radially extending opening therein to receive said striker stem, and a second shoulder formed on the other of said fuse body elements and engaging the outer peripheral surface of said washer and holding the same in contact with said collar element.

6. A percussion fuse according to claim 5 including a gasket interposed between the collar element and the shoulder upon which said element is supported.

'7. In a percussion fuse for projectiles of the sensitive type adapted to operate by the driving in of the striker upon impact, a fuse body having formed in the forward end thereof an open ended chamber, a striker member having an enlarged head housed in said chamber adjacent the open end thereof and a stem extending into and guided by an axial passageway formed in said fuse body, a shoulder fixed with respect to said fuse body,

a collar element formed integrally with said striker stem and resting upon said shoulder so as to normally prevent inward movement of said striker member relative to said fuse body, said collar element being so constructed as to resist Without fracture the static stresses produced upon firing of the projectile due to the inertia of the striker member but to shear easily from the striker stem under the effect of even relatively slight dynamic stresses produced upon impact, and means for preventing movement of said striker member outwardly through the open end of said chamber, said means comprising a washer positioned within said chamber and clamped between the outer surface of said collar element and a shoulder formed on said fuse body, said washer having a radially extending slot formed therein to receive said striker stem.

8. In a percussion fuse for projectiles of the sensitive type adapted to operate by the driving in of the striker upon impact, a fuse body having formed in the forward end thereof an open ended chamber, a sleeve member mounted axially of said fuse body with its outer end extending into said chamber, a recess formed in the inner end of said sleeve member, a percussion cap housed in said recess, a striker member having an enlarged head housed in said chamber adjacent the open end thereof and a stem extending into and guided by the bore of said sleeve member, and a collar element formed integrally with said striker stem and resting upon the upper end of said sleeve member so as to normally prevent inward movement of said striker member relative to said fuse body, said collar element being so constructed as to resist without fracture the static stresses produced upon firing of the projectile due to the inertia of the striker member but to shear easily from the striker stemunder the effect of even relatively slight dynamic stresses produced upon impact.

LEON EMILE REMONDY. 

